1. Field of the Invention
The present invention relates to a tracking error (TE) detection device using a DPD (differential phase detection) method which is employed in an optical disc apparatus, for example, and the optical disc apparatus.
2. Description of the Related Art
In general, optical controllers include TE (tracking error) detection devices (circuits) employing DPD methods in order to generate tracking error signals in ROM discs. The TE detection devices employing the DPD methods are currently realized by analog circuits which operate at high speed and which have high accuracies (refer to Japanese Patent No. 3336778, Japanese Unexamined Patent Application Publication No. 57-191839, Japanese Unexamined Patent Application Publication No. 57-181433, Japanese Unexamined Patent Application Publication No. 63-148433, Japanese Unexamined Patent Application Publication No. 07-296395, Japanese Unexamined Patent Application Publication No. 63-131334, Japanese Patent No. 3065993, Japanese Patent No. 3439393, Japanese Unexamined Patent Application Publication No. 2006-260645, and Japanese Patent No. 3769888, for example)
In response to recent development of a system LSI (large-scale integration) technique, a technique of integrating analog signal processing and digital signal processing so that the analog signal processing and the digital signal processing are performed using an identical chip has been developed. This technique is also applied to controller chips of optical discs. In response to such development of digital signal processing, there are strong demands for integrations in order to obtain digital chips in TE detection devices employing DPD methods.
To meet such demands, three techniques will be described hereinafter as first to third examples.